/*
 *  Copyright 2013 National Institute of Advanced Industrial Science and Technology
 *  
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *  
 *      http://www.apache.org/licenses/LICENSE-2.0
 *  
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

package org.sss.util;

import java.util.HashMap;
import java.util.Map;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class FactoryRegistry<K, T> {
  private static Logger logger = LoggerFactory.getLogger(FactoryRegistry.class);
  
  private String name;
  private Map<K, Factory<T>> dic = new HashMap<K, Factory<T>>();
  
  public FactoryRegistry(String name) {
    this.name = name;
  }
  
  public void register(K key, Factory<T> f) {
    if (dic.containsKey(key)) {
      logger.warn("Overwrites the {} factory of {}.", name, key.toString());
    }
    dic.put(key, f);
  }
  
  public Factory<T> get(K key) {
    Factory<T> f = dic.get(key);

    if (f == null) {
      return createDefaultFactory(key);
    } else {
      return f;
    }
  }
  
  protected Factory<T> createDefaultFactory(K key) {
    return null;
  }
}
